Add PPTX, XLSX, DOCX, and PDF Generation to Any Claude API Call With Two Beta Headers

TL;DR: Anthropic's Agent Skills API generates real Office documents from a plain messages.create call — add a container.skills param and two beta headers, retrieve the file via the Files API.

The Anthropic API now includes four pre-built "Agent Skills" for document creation: PowerPoint (pptx), Excel (xlsx), Word (docx), and PDF (pdf). Enabling one adds a single extra parameter to your existing messages.create call — no separate microservice, no file-parsing boilerplate.

How it works

Claude writes Python that produces the document, executes it in a sandboxed code-execution container, and returns a file_id you download via the Files API. You send the request, you download the result.

The minimal Python call

import anthropic
from pathlib import Path
import tempfile

client = anthropic.Anthropic()

response = client.beta.messages.create(
    model="claude-opus-4-8",
    max_tokens=16000,
    betas=["code-execution-2025-08-25", "skills-2025-10-02"],
    container={
        "skills": [{"type": "anthropic", "skill_id": "pptx", "version": "latest"}]
    },
    messages=[{"role": "user", "content": "Create a 5-slide Q2 results deck"}],
    tools=[{"type": "code_execution_20250825", "name": "code_execution"}],
)

Two beta headers: code-execution-2025-08-25 and skills-2025-10-02. The container.skills array picks the skill. Swap pptx for xlsx, docx, or pdf.

Getting the file back

file_id = None
for block in response.content:
    if block.type == "code_execution_tool_result":
        if block.content.type == "code_execution_result":
            for output in block.content.content:
                file_id = output.file_id

if file_id:
    out = Path(tempfile.gettempdir()) / "output.pptx"
    client.beta.files.download(file_id=file_id).write_to_file(out)

When to reach for this

• Report pipelines: generate a formatted PDF/PPTX from structured data without a separate templating layer
• Agent deliverables: give your agent a tool that outputs an actual file (Excel model, Word brief) instead of Markdown
• Automation: replace scripts that call python-docx directly — let Claude handle the structure and formatting

List available skills at runtime: client.beta.skills.list(source="anthropic") returns pptx, xlsx, docx, pdf with display titles. Custom skills (domain expertise packaged as a skill and uploaded via the API) are also available through the Agent Skills Cookbook.

Sources: Agent Skills quickstart — Anthropic Platform Docs, Agent Skills overview, anthropics/skills — GitHub